Buildings are designed for daylight utilization by bringing in natural light from a side of a building without having direct radiation protection, where direct radiation has high energy causing many problems, such as glares and ultraviolet radiation (UV). UV radiation is known to be harmful to the eyes and health. The heat from direct rays affects human thermal comfort, cooling loads, and power consumption of air conditioning systems. In addition, ultraviolet (UV) rays from direct sunlight accelerate the deterioration process of human skin, interior finishing materials, and furniture.
Using shading to prevent direct radiation may be accomplished by various techniques, such as the use of various materials in various forms. Many of the shadings used in the past and present consist of long and flat panels, which include horizontal panels, vertical panels, or egg-crates (mixed horizontal and vertical panels) with both kinds of deadlocks and an adjustable angle. This may include the use of opaque or transparent materials to block the direct sunlight and perforate in various ways to obtain some light and provide outside views.
Horizontal shading panels include a sun shading device of European Patent Application No. EP20090151751, filed Jan. 30, 2009, the horizontal sun-shading device with adjustable louvers of Chinese Patent Application No. CN201433527 Y, published Mar. 31, 2010, and the solar window shade of U.S. Pat. No. 8,528,621 B2, published Sep. 10, 2013.
Vertical shading panels include the window blind of U.S. Pat. No. 2,882,563 A, published Apr. 21, 1959, and the split vertical window blind of U.S. Pat. No. 8,746,319 B1, published Jun. 10, 2014.
Vertical and horizontal shading screens and other solar screen panels include the self-regulating solar window device of U.S. Pat. No. 4,279,240 A, published Jul. 21, 1981, flat sheet panels, such as the variable screening U.S. Patent Publication No. 2012/0061029 A1, published Mar. 15, 2012, now issued as U.S. Pat. No. 8,960,259, and the curtain system of U.S. Patent Publication No. 2013/0139976 A1, published Jun. 6, 2013, now issued as U.S. Pat. No. 8,979,418.
Solar shading currently has several drawbacks. In general, the deadlock shadings are unable to prevent direct light throughout the year. In order to prevent direct light at all times, the panels or materials must be overlapped, which is wasteful and obscures external views. Sunscreen panels need to be angled in a direction to protect direct sunlight and are not easy to use. The use of electronics equipment to adjust shading devices angles are costly in terms of investment and maintenance, and may cause problems in the long term.
The sunscreen opaque panels, which have holes or are perforated evenly, allow building users to perceive an external view, but they are still not efficient or capable of protecting against direct sunlight year round. Increasing the thickness of the sheet or having shadings together with the voids may be better for sun protection, but are still inefficient due to materials being overlapped more than necessary.